The present invention relates generally to activity monitors and diet monitors and, more specifically, to a device that combines both diet and activity monitoring.
Management of diet, health, and fitness has drawn increasing amounts of attention as their importance has been recognized, and as consumers around the world have struggled to balance busy lives with fitness and proper diet. Despite the recognized importance of good health, consumers, on average, are becoming increasingly obese. This has resulted in a strong demand for devices and methods that assist individuals in setting and reaching dietary and fitness goals. Currently available devices and methods fail to meet the needs of average consumers.
There are serious problems with conventional weight loss programs. Weight change is related to the user""s net caloric balance, the difference between caloric intake and caloric expenditure. However, determination of caloric intake and caloric expenditure are both problematic.
There are numerous difficulties in accurately determining caloric intake. In some diet programs printed or electronic lists are used that provide the nutrition content of a wide variety of food. The consumer keeps a diet log of all foods consumed each day in order to determine their total nutritional intake. These systems typically are laborious to use and only the most dedicated consumer will accurately use these approaches. For example, a consumer must take the time to accurately record the foods consumed each day. Obviously, recognition of foods consumed is most accurate if done at the time the foods are consumed. However, many individuals feel too rushed to record the foods consumed at the time and postpone recording for later in the day or week. Also, some consumers are embarrassed to be observed recording food intake during or following a meal. This also motivates the user to wait to record their consumption until later. Obviously, accuracy suffers the more time passes between consumption and recordation. An individual may entirely forget that they had a snack or two earlier in the day or week, leading to undercounting of consumption.
Determining total energy expenditure is also difficult. The total energy expenditure of a person comprises a resting metabolic component and a physical activity component. Total energy expenditure (TEE) is the sum of resting energy expenditure (REE) and activity energy expenditure (AEE), i.e. TEE=AEE+REE. Weight loss occurs if total energy expenditure (TEE) exceeds total caloric intake over a given time period. As discussed by Remmereit in U.S. Pat. No. 6,034,132, 70 percent of total energy expenditure for a typical person is due to their resting metabolic rate (RMR). In a conventional diet program, RMR is estimated from the height, weight, age, and gender of the person, for example using the Harris-Benedict equation. This equation, well known to those skilled in the nutritional arts, is given in U.S. Pat. No. 5,839,901 to Karkanen, and in U.S. Pat. No. 5,639,471 to Chait et al. There are serious inadequacies in using the Harris-Benedict equation (or any similar equation) in a weight loss program. The Harris-Benedict equation provides only an estimated RMR, which is an average value for people of similar height, weight, age, and gender. However, due to natural variations in physiology, the equation may not be accurate for a specific individual.
Conventional weight loss programs use an estimated total energy expenditure (TEE) based on estimates of activity levels, and estimates of resting energy expenditure (REE) from the Harris-Benedict equation. However, unless the resting energy expenditure (REE) and the activity energy expenditure (AEE) are estimated accurately, the person""s caloric balance cannot be known accurately, and the outcome of a weight loss program is likely to be unsatisfactory.
Some users attempt to track their activity energy expenditure (AEE), either for weight loss or general fitness purposes. In the simplest approach the individual maintains an exercise log of activities conducted, such as distances walked or jogged. Various graphs and tables can then provide an estimate of the calories burned during these activities. As with recording consumption, an individual may fail to accurately record the type and duration of activity undertaken leading to inaccurate recordation. Also, an individual may not know how far or fast they ran or walked. A variety of pedometers are available to assist with this task. Pedometers include some type of stride counter in order to count the number of strides or paces taken by the individual. The devices may be calibrated to allow them to determine the distance traveled with reasonable accuracy. Through the use of timers, they may also be able to determine the speed and duration of activity. Pedometers typically fail to take into consideration changes of elevation, changes in length of stride and changes in intensity. For example, a runner may combine slow walking with brisk running during an exercise session. By combining total number of strides and duration of activity, the pedometer may only determine average speed, not instantaneous speed.
U.S. Pat. Nos. 6,002,982 and 6,148,262 to Fry; U.S. Pat. No. 6,013,007 to Root et al; U.S. Pat. Nos. 6,009,138 to Slusky; and U.S. Pat. Nos. 6,032,108 to Seiple et al each disclose improved activity monitors utilizing a global positioning system (GPS). The devices track an individual""s position over time, using the GPS network. By periodically or instantaneously comparing position and time, such a device is capable of determining a performance profile with better accuracy than a typical pedometer.
Devices are also available for monitoring and tracking heart rate. The most popular of these devices are sold by Polar Electro Oy of Finland. These heart rate monitors includes a wristwatch-style display unit and a chest strap with a heart rate sensor. The chest strap and display unit communicate wirelessly. The devices are capable of accurately monitoring heart rate, which correlates reasonably well with exercise intensity. Advanced devices include the ability to track heart rate over time so that a heart rate profile may be produced.
Each of the above-discussed activity monitors fails to consider the dietary intake portion of total health management. Instead, they are directed merely to activity monitoring. In light of this, there remains a need for a device that combines activity monitoring and diet monitoring, that is easy to use and provides accurate results.
The present invention improves on the prior art by providing a combination diet and activity monitoring device for monitoring both the consumption and activity of the subject. The effectiveness of weight management programs may be improved through a more accurate determination of caloric balance. Improved determination of caloric balance may be obtained by more accurate determinations of total energy expenditure, (the sum of resting energy expenditure and activity energy expenditure) and caloric intake. The present invention focuses on improving the determination of activity energy expenditure and caloric intake. Resting energy expenditure, the energy expended by an individual at rest, may be accurately determined using an indirect calorimeter, such as described in co-pending patent application Ser. No. 09/630,398, incorporated herein by reference. As discussed in this application, resting energy expenditure is based on resting metabolic rate. Resting metabolic rate changes over time, especially when the subject changes their diet or exercise patterns. Therefore, it is preferable to periodically measure resting metabolic rate so that accurate determinations of resting energy expenditure are available during a weight management program.
Determination of activity energy expenditure, which combined with resting energy expenditure provides total energy expenditure, may be obtained by monitoring a subject""s activity on a regular basis. The monitoring device according to the present invention includes a body activity monitor for monitoring the body activity of the subject. The body activity monitor is operable to output a signal indicative of the subject""s body activity. An activity calculator may also be provided, which receives the activity; indicative signal and determines a body activity level and/or energy expenditure for the subject. The body activity monitor may be integral with the monitoring device, or may be part of an auxiliary device. For example, the monitoring device according to the present invention may take the form factor of a wristwatch-style device or a belt or clothing-mounted monitor. In a wristwatch-style device, the body activity monitor may comprise a heart rate monitor, monitoring the heart rate of the subject. The heart rate of the subject increases with activity and decreases when the subject is resting. By calibrating the activity monitor, the subject""s activity level and activity related energy expenditure may be determined. The activity monitor may be calibrated using an indirect calorimeter, as described in co-pending patent application Ser. No. 09/684,440, incorporated herein by reference. The heart rate monitor may form part of the wristwatch-style monitoring device and sense heart rate in the subject""s wrist or other appendage. Alternatively, a separate heart rate sensor may be provided such as a chest strap, that communicates with the monitoring device, preferably using a wireless link. A belt or clothing mounted monitoring device may also include a heart rate monitor as the body activity monitoring portion.
The body activity monitor which forms part of the monitoring device according to the present invention may alternatively comprise a motion sensor such as a mechanical pendulum or a single or multi axis accelerometer. An accelerometer is preferred as it may provide information on body movement as well as the direction and intensity of the movement. The motion sensor may form part of the wristwatch or belt or clothing mounted monitoring device or may be part of a separate accessory that communicates with the monitoring device. For example, if the monitoring device according to the present invention takes the form of a belt or clothing mounted housing, the accelerometer may be disposed in the housing and sense motion of the housing. Because the housing is attached to the subject""s belt or clothing, motion of the housing correlates with movement of the subject. Once again, the body activity monitor may be calibrated to determine activity related energy expenditure using an indirect calorimeter.
As another alternative, the body activity monitor may include multiple modes for recording of variety of activities, such as swimming, biking, and use of stationary exercise equipment. The body activity monitor may then be placed in the mode corresponding to an activity that the subject undertakes. The subject presses a start button and the body activity monitor will record the duration of the activity. The monitoring device may then determine an activity level based on the duration of the activity and the estimated intensity. The activity level may be adjusted by the user to increase the accuracy of the estimate. Alternatively, the body activity monitor portion of the monitoring device may communicate with the exercise equipment or system of equipment being used by the subject to allow transfer of accurate data related to exercise. As one simple alternative, the body activity monitor may allow the subject to create time-stamped exercise flags, corresponding to when exercise is undertaken. To create an exercise flag, the subject manipulates a control on the monitoring device at the time of the activity. Later, the time or the duration of the activity may be recalled and an actual activity level be entered for tracking purposes.
It is preferred that the monitoring device according to the present invention forms part of the system including a local remote computing device to which data from the monitoring device may be downloaded for further manipulation. For example, at the end of the day, the subject may download data from the monitoring device to a home PC. The subject may then view the activity and consumption data and have it during the day. The subject may then be prompted to provide additional information about events such as exercise and food flags. This data may be used as part of a determination of total caloric balance and as part of a weight loss program.
The monitoring device according to the present invention also preferably includes a consumption notation control for use by the subject to indicate when the subject consumes food. This consumption notation control preferably provides a very simple means for the subject to note when consumption occurs and avoids the embarrassment and difficulty of recording the actual foods consumed during or immediately following consumption of the foods. In one embodiment of the present invention, the subject manipulate a control on the monitoring device each time they consume food, whether the food is a snack or a meal. The monitoring device records the time the control was manipulated and creates a xe2x80x9cfood flagxe2x80x9d. Later, the subject may use the food flags to help them recall what they ate. Software on the local or remote computing device may assist in theses determinations by presenting options on what was consumed based on past behavior and software settings. Alternatively, food flags may also have a duration component. For example, a subject may manipulate the consumption notation control once at the beginning of the consumption event and again at the end of the consumption event. The duration of the event provides additional data for use in determining what foods were consumed. As another alternative, the consumption notation control may include and audio and/or video recording device, allowing the subject to make audio and/or video notations as to what was consumed. For example, the monitoring device may include a recording mechanism such as a digital recording means. In addition to or alternatively to the food flags, the subject may make a brief audio recording as to what was consumed. Alternatively, or additionally the monitoring device may include a video recording system such as a miniaturized camera. The subject may then photograph what was consumed to allow an accurate determination of consumption at a later time. The use of audio or video recording allows additional functionality. For example, the local or remote computing device may be operable to provide voice recognition on downloaded audio files from the monitoring device. Then, the subject""s auditory notes may be transcribed into written text for later reference by the user. Alternatively, the software may determine what foods were consumed based on the auditory notation. Similar functionality may be provided with video recordings such as digital pictures. The digital pictures may be transmitted to a remote site where an administrative person reviews the picture and records what was consumed and transmits this recording back to the subject. This may be provided on a subscription basis. Alternatively, software could be provided which performs an image analysis on the digital picture to assist in determining the foods consumed. As another alternative, the monitoring device according to the present invention may include a scanning device to allow it to scan and record bar codes and similar coded markings. This functionality may be incorporated into the digital camera or may be separate. Also, the scanner may form a separate unit from the remainder of the monitoring device and communicate with the monitoring device through a wire or wireless connection. The bar code scanning may be used to scan foods to be consumed as well as other information such as data concerning exercise.
The monitoring device according to the present invention preferably also includes a timer that outputs a time indicative signal for use in time stamping food flags and exercise flags and for use in tracking activity during the day.
The diet and activity monitoring device may communicate with local and remote computers using a wired or wireless connection, as well as through transfer of memory modules. The local or remote computers may allow additional or easier access to advance functions, such as diet and activity tracking over longer periods of time.